Motorized surgical instruments may use a variety of method to power moving components. For example, a motorized surgical instrument used for dissecting bone or tissue may use a pneumatic motor to power a dissecting tool. Pressurized fluid power the motor, which may be mechanically linked to the dissecting tool by means of a rotatable shaft. The application of pressurized fluid to the motor results in rotation of the shaft, which in turn rotates the dissecting tool.
Difficulties may arise in the assembly and operation of pneumatic surgical instruments. Conventional pneumatic surgical instruments house the rotatable shaft in a rotor housing chamber defined by a rotor housing. In order to allow the shaft to rotate freely in the rotor housing chamber, a plurality of components are coupled to the rotor housing such as, for example, bearings, bearing housings, fluid distributors, and a variety of other components known in the art. In addition, in order to ensure that these components are properly positioned in the assembly, an alignment pin may be used to align the components with the rotor housing and the shaft. As the number of components coupled to the rotor housing grows, the tolerance between the components and the rotor housing make the repeatability of the assembly of the surgical instrument itself difficult.
Therefore, what is needed is an improved assembly for a surgical instrument.